Method and apparatus for indirect bonding of orthodontic appliances

ABSTRACT

An indirect bonding apparatus is made by initially placing spacer material over a replica of the patient&#39;s tooth structure. A tray is then formed over the spacer material and hardened. Next, the spacer material is removed from the tooth replica and orthodontic appliances are placed on the replica at desired locations. A matrix material is placed between the tray and the replica and allowed to harden. Optionally, the apparatus includes features for facilitating removal of the transfer apparatus after the bonding procedure has been completed, and features for applying firm, uniform pressure to the appliances during the bonding procedure. Other aspects of indirect bonding are also described.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to methods and apparatus for bonding orthodonticappliances such as brackets to a patient's teeth. The present inventionfacilitates precise positioning of the appliances in predeterminedlocations on the teeth and helps to minimize the amount of the patient'stime that is spent in the orthodontic operatory.

2. Description of the Related Art

Orthodontic treatment involves movement of malpositioned teeth todesired locations in the oral cavity. Orthodontic treatment can improvethe patient's facial appearance, especially in instances where the teethare noticeably crooked or where the jaws are out of alignment with eachother. Orthodontic treatment can also enhance the function of the teethby providing better occlusion while eating.

One common type of orthodontic treatment involves the use of tiny,slotted appliances known as brackets. The brackets are fixed to thepatient's teeth and an archwire is placed in the slot of each bracket.The archwire forms a track to guide movement of teeth to desiredlocations.

The ends of orthodontic archwires are often connected to smallappliances known as buccal tubes that are, in turn, secured to thepatient's molar teeth. In many instances, a set of brackets, buccaltubes and an archwire is provided for each of the patient's upper andlower dental arches. The brackets, buccal tubes and archwires arecommonly referred to collectively as “braces”.

In many types of orthodontic techniques, the precise position of theappliances on the teeth is an important factor for helping to ensurethat the teeth move to their intended final positions. For example, onecommon type of orthodontic treatment technique is known as the“straight-wire” technique, where the archwire lies in a horizontal planeat the conclusion of treatment. If, for example, a bracket is attachedto the tooth at a location that is too close to the occlusal or outertip of the tooth, the orthodontist using a straight-wire technique willlikely find that the tooth in its final position is unduly intruded. Onthe other hand, if the bracket is attached to the tooth at a locationcloser to the gingiva than is appropriate, it is likely that the finalposition of the tooth will be more extruded than desired.

In general, orthodontic appliances that are adapted to be adhesivelybonded to the patient's teeth are placed on the teeth by either one oftwo methods: a direct bonding method, or an indirect bonding method. Inthe direct bonding method, the appliance and adhesive are grasped with apair of tweezers or other hand instrument and placed by the practitioneron the surface of the tooth in an approximate desired location. Next,the appliance is shifted along the surface of the tooth as needed untilthe practitioner is satisfied with its position. Once the appliance isin its precise, intended location, the appliance is pressed firmly ontothe tooth to seat the appliance in the adhesive. Excess adhesive inareas adjacent the base of the appliance is removed, and the adhesive isthen allowed to cure and fix the appliance firmly in place. Typicaladhesives include light-curable adhesives that begin to harden uponexposure to actinic radiation, and two-component chemical-cure adhesivesthat begin to harden when the components are mixed together.

While the direct bonding technique described above is in widespread useand is considered satisfactory by many, there are shortcomings that areinherent with such a technique. For example, access to surfaces ofmalposed teeth may be difficult. In some instances, and particularly inconnection with posterior teeth, the practitioner may have difficultyseeing the precise position of the bracket relative to the toothsurface. Additionally, the appliance may be unintentionally bumped fromits intended location during the time that the excess adhesive is beingremoved adjacent the base of the appliance.

Another problem associated with the direct bonding technique describedabove concerns the significant length of time needed to carry out theprocedure of bonding each appliance to each individual tooth. Typically,the practitioner will attempt to ensure that each appliance ispositioned in its precise, intended location before the adhesive iscured, and some time may be necessary before the practitioner issatisfied with the location of each appliance. At the same time,however, the patient may experience discomfort and have difficulty inremaining relatively motionless, especially if the patient is anadolescent. As can be appreciated, there are aspects of the directbonding technique that can be considered a nuisance for both thepractitioner and for the patient.

Indirect bonding techniques often avoid many of the problems notedabove. In general, indirect bonding techniques known in the past haveinvolved the use of a transfer tray having a shape that matches theconfiguration of at least part of a patient's dental arch. A set ofappliances such as brackets are releasably connected to the tray atcertain, predetermined locations. Adhesive is applied to the base ofeach appliance, and the tray is then placed over the patient's teethuntil such time as the adhesive hardens. Next, the tray is detached fromthe teeth as well as from the appliances, with the result that all ofthe appliances previously connected to the tray are now bonded to therespective teeth at their intended, predetermined locations.

In more detail, one method of indirect bonding of orthodontic appliancesincludes the steps of taking an impression of each of the patient'sdental arches and then making a replica plaster or “stone” model fromeach impression. Optionally, a soap solution (such as Model Glow brandsolution from Whip Mix Corporation) or wax is applied to the stonemodel. A separation solution (such as COE-SEP brand tinfoil substitutefrom GC America, Inc.) is then applied to the stone model and allowed todry. If desired, the teeth of the model can be marked with a pencil toassist in placing the brackets in ideal positions.

Next, the brackets are bonded to the stone models. Optionally, thebonding adhesive can be a chemical curing adhesive (such as Concisebrand adhesive from 3M) or a light-curable adhesive (such as TransbondXT brand adhesive or Transbond LR brand adhesive, from 3M). Optionally,the brackets may be adhesive precoated brackets such as those describedin U.S. Pat. Nos. 5,015,180, 5,172,809, 5,354,199 and 5,429,229.

A transfer tray is then made by placing a matrix material over the modelas well as over the brackets placed on the model. For example, a plasticsheet matrix material may be held by a frame and exposed to radiantheat. Once the plastic sheet material has softened, it is placed overthe model and the brackets. Air in the space between the sheet materialand the model is then evacuated, and the plastic sheet material assumesa configuration that precisely matches the shape of the replica teeth ofthe stone model and the attached brackets.

The plastic material is then allowed to cool and harden to form a tray.The tray and the brackets (which are embedded in an interior wall of thetray) are then detached from the stone model and sides of the tray aretrimmed as may be desired. Once the patient has returned to the office,a quantity of adhesive is placed on the base of bracket, and the traywith the embedded brackets is then placed over the matching portions ofthe patient's dental arch. Since the configuration of the interior ofthe tray closely matches the respective portions of the patient's dentalarch, each bracket is ultimately positioned on the patient's teeth atprecisely the same location that corresponds to the previous location ofthe same bracket on the stone model.

Both light-curable adhesives and chemical curing adhesives have beenused in the past in indirect bonding techniques to secure the bracketsto the patient's teeth. If a light-curable adhesive is used, the tray ispreferably transparent or translucent. If a two-component chemicalcuring adhesive is used, the components can be mixed togetherimmediately before application of the adhesive to the brackets.Alternatively, one component may be placed on each bracket base and theother component may be placed on the tooth surface. In either case,placing of the tray with the embedded brackets on corresponding portionsof the patient's dental arch enables the brackets to be bonded to theteeth as a group using only a short amount of time that the patient isoccupying the chair in the operatory. With such a technique, individualplacement and positioning of each bracket in seriatim fashion on theteeth is avoided.

A variety of transfer trays and materials for transfer trays have beenproposed in the past. For example, some practitioners use a soft sheetmaterial (such as Bioplast tray material from Scheu-Dental GmbH) forplacement over the stone model and the appliances on the model. A vacuumis applied to draw the soft material into intimate contact with themodel and the appliances on the model. Next, a stiffer sheet material(such as Biocryl sheet material, from Scheu-Dental GmbH or Great LakesOrthodontics, Ltd.) is formed over the softer sheet material, againusing a vacuum forming technique. The stiffer material provides abackbone to the tray, while the softer material initially holds theappliances and yet is sufficiently flexible to release from theappliances after the appliances have been fixed to the patient's teeth.

It has also been proposed in the past to use a silicone impressionmaterial or a bite registration material (such as Memosil 2, fromHeraeus-Kulzer GmbH-& Co. KG). The silicone material is applied over theappliances that are attached to the study model so that the appliancesare partially encapsulated.

In an article entitled “A New Look at Indirect Bonding” by Moskowitz etal. (Journal of Clinical Orthodontics, Volume XXX, Number 5, May 1996,pages 277 et sec.), a technique for making indirect bonding trays isdescribed using Reprosil impression material (from DentsplyInternational). The impression material is placed with a syringe overbrackets that have been previously placed on a stone model. Next, asheet of clear thermoplastic material is drawn down over the impressionmaterial using a vacuum-forming technique. The resultant transfer trayis then removed from the model for subsequent placement on the patient'sdental arch.

Indirect bonding techniques offer a number of advantages over directbonding techniques. For one thing, and as indicated above, it ispossible to bond a plurality of brackets to a patient's dental archsimultaneously, thereby avoiding the need to bond each appliance inindividual fashion. In addition, the indirect bonding tray helps tolocate all of the brackets in their proper, intended positions such thatadjustment of each bracket on the surface of the tooth before bonding isavoided. The increased placement accuracy of the appliances that isoften afforded by indirect bonding techniques helps ensure that thepatient's teeth are moved to their proper, intended positions at theconclusion of treatment.

While the indirect bonding techniques as described above have provensatisfactory for many practitioners, there is a continuing need toimprove the state of the art. Moreover, the provision of a transfer traywith additional features that facilitate the technique of indirectbonding would be beneficial, such as features that facilitate properattachment of the appliances to the patient's tooth surfaces and/orfeatures that enhance detachment of the transfer tray subsequent tobonding.

SUMMARY OF THE INVENTION

The present invention relates to improved methods and apparatus forindirect bonding of orthodontic appliances. In one aspect, the inventionrelates to a transfer apparatus used in indirect bonding, wherein theapparatus includes a tray that is made in a forming technique thatincludes the use of a spacer material placed over a replica of thepatient's tooth structure. The spacer material forms a-region thatsubsequently receives a matrix material. The matrix material assumes theconfiguration of the replica and also serves to releasably retain one ormore appliances in the apparatus.

Preferably, the matrix material is relatively soft and has a Shore Ahardness in the range of about 10 to about 80. Furthermore, the matrixmaterial before curing preferably has a viscosity of less than about60,000 centipoise (“cp”). The matrix material intimately contacts eachappliance for satisfactory retention, and also easily releases from theappliance when desired after bonding of the appliance to the tooth iscomplete. The matrix material also has sufficient flexibility toaccommodate minor tooth movement between the time that the impression istaken for making the replica and the time that the resultant transferapparatus is used to bond the appliances to the teeth.

The present invention also is directed toward a number of improvementsfor indirect transfer apparatus, as will be described in more detailbelow. Examples of such improvements include structure for facilitatingthe application of uniform pressure during the bonding procedure, usingpressurized air or a source of vacuum. Other improvements relate tostructure for facilitating detachment of the apparatus from thepatient's dental arch once the bonding procedure has been completed.

In more detail, the present invention in one aspect relates to a methodof making orthodontic transfer apparatus for indirect bonding of one ormore orthodontic appliances. In this method, a replica of a patient'stooth structure is made, and a spacer material is placed over at least aportion of the replica. A tray is formed over at least a part of thereplica including at least part of the spacer material. The tray isremoved from the replica and from the spacer material. The spacermaterial is detached from the replica, and one or more orthodonticappliances are placed on the replica to make an orthodontic treatmentmodel. A quantity of matrix material is applied to either the tray or tothe model, and the tray is positioned over the model such that thematrix material is received between the tray and the model. The matrixmaterial is allowed to harden.

The present invention also relates to transfer apparatus for use inindirect bonding of orthodontic appliances. The apparatus includes atray having a channel, and a curable matrix material received in thechannel. At least one orthodontic appliance is received in the matrixmaterial. The matrix material has a viscosity before curing that is lessthan about 60,000 cp.

Another aspect of the present invention also relates to a transferapparatus for use in indirect bonding of orthodontic appliances. In thisaspect, the transfer apparatus includes a tray having a channel, and amatrix material received in the channel. The matrix material has acavity with a configuration matching at least a portion of the dentalpatient's tooth structure. At least one orthodontic appliance isreceived in the matrix material in a location next to the cavity. Thematrix material has a Shore A hardness that in the range of about 10 toabout 80.

The present invention in another aspect is also directed to a transferapparatus for use in indirect bonding of orthodontic appliances. In thisaspect, the transfer apparatus includes a matrix material having acavity with a configuration matching at least a portion of the dentalpatient's tooth structure. At least one orthodontic appliance isreceived in the matrix material in a location next to the cavity. Apassageway extends next to the cavity with an outlet for connection to asource of fluid having a pressure other than atmospheric pressure.

Another aspect of the present invention also relates to a transferapparatus for use in indirect bonding of orthodontic appliances. In thisaspect, the transfer apparatus includes a matrix material having acavity with a configuration matching at least a portion of the dentalpatient's tooth structure. At least one orthodontic appliance isreceived in the matrix material in a location next to the cavity. Atleast one flexible bladder is next to the matrix material. The transferapparatus also includes a conduit for connecting each bladder to asource of pressurized air.

In yet another aspect of the invention, a transfer apparatus is providedfor use in indirect bonding of orthodontic appliances. In this aspect,the transfer apparatus includes a matrix material having an elongatedcavity with a configuration matching at least a portion of a dentalpatient's tooth structure. At least one orthodontic appliance isreceived in the matrix material in a location next to the cavity. Anelongated flexible cord is at least partially embedded in the matrixmaterial and extends in a direction generally along the longitudinalaxis of the cavity.

Another embodiment of the present invention is directed to a method oforthodontic indirect bonding. In this method, an orthodontic transferapparatus is provided comprising a tray, a quantity of matrix materialreceived in the tray, and one or more orthodontic appliances at leastpartially embedded in the matrix material, wherein the tray has a ShoreA hardness that is greater than the Shore A hardness of the matrixmaterial. The tray is detached from the matrix material. Subsequently,the matrix material is applied to one of the patient's dental arches inorder to position at least one orthodontic appliance on the patient'stooth structure.

The present invention is also directed in another aspect to a method oforthodontic indirect bonding. In this method, a replica of a patient'stooth structure is made, and a spacer material is placed over at least aportion of the replica. A tray is formed over at least a part of thereplica including at least part of the spacer material. The tray isremoved from the replica and from the spacer material. The spacermaterial is detached from the replica, and one or more orthodonticappliances are placed on the replica to make an orthodontic treatmentmodel. A quantity of matrix material is applied to either the tray or tothe model, and the tray is positioned over the model such that thematrix material is received between the tray and the model. The matrixmaterial is allowed to harden. The matrix material is moved into theoral cavity of the patient in order to position at least one orthodonticappliance on the patient's tooth structure.

These and other aspects of the invention are described in more detailbelow and are illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top and front view showing a physical replica of one dentalarch of an orthodontic patient, illustrating an example of a replica ofa patient's tooth structure and adjacent gingival tissue as they mightappear before the commencement of treatment;

FIG. 2 is a view of the dental arch replica shown in FIG. 1, along withspacer material that has been applied to the replica;

FIG. 3 is an enlarged side cross-sectional view of one of the replicateeth illustrated in FIG. 2 along with the spacer material;

FIG. 4 is a view somewhat similar to FIG. 3, additionally showing a traythat has been formed over the spacer material;

FIG. 5 is a view of the tooth structure replica illustrated in FIG. 1after the spacer material and the tray have been removed, andadditionally showing a number of orthodontic appliances that have beenplaced in predetermined positions on the replica;

FIG. 6 is an enlarged side cross-sectional view of one of the replicateeth and appliances depicted in FIG. 5, and additionally showing aquantity of matrix material which has been placed between the replicaand the tray shown in FIG. 4 after the replica and the tray have beeninverted to make a transfer apparatus;

FIG. 7 is an enlarged side cross-sectional view showing the act ofapplying the transfer apparatus to one of the patient's teeth;

FIG. 8 is an enlarged side cross-sectional view of a transfer apparatusfor indirect bonding according to another embodiment of the invention;

FIG. 9 is a view somewhat similar to FIG. 8 except showing a transferapparatus in accordance with another embodiment of the invention;

FIG. 10 is a view somewhat similar to FIG. 8 except showing a transferapparatus according to yet another embodiment of the invention; and

FIG. 11 is a view somewhat similar to FIG. 8 except showing a transferapparatus in accordance with still another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A method for indirect bonding of one or more orthodontic appliances inaccordance with one aspect of the present invention will first bedescribed. FIG. 1 illustrates a replica 20 of a portion of a dental archof an orthodontic patient. For exemplary purposes, the replica 20represents the patient's lower dental arch. However, a replica of apatient's upper dental arch may be provided as an addition to or as analternative to the lower dental arch replica as shown. As a furtheroption, the replica 20 may represent only a portion of a dental arch,such as a quadrant of an arch or only one or two teeth of a dental arch.In the example illustrated, the replica 20 includes a number of replicateeth 22, corresponding to each tooth of the patient's lower dentalarch.

Optionally, the replica 20 is made by first taking an impression of thepatient's lower dental arch, using care to avoid undue distortion.Optionally, an alginate impression material is used such as Unijel IIalginate impression material from 3M Unitek. Alternatively, ahydrocolloid or vinyl polysiloxane impression material may also be used,such as Position Penta brand vinyl polysiloxane impression material from3M ESPE.

The model or replica 20 is then made from the impression. Optionally,the replica 20 is a “stone” model made from plaster of Paris, using careto avoid bubbles in the model. If small voids are present, the voids canbe filled with a small, additional quantity of plaster of Paris. As anoption, the replica 20 includes only the replica teeth 22 and sufficientreplica gingival tissue 24 to hold the replica teeth 22 together.

As an alternative, the replica 20 may be made using digital data that isrepresentative of the patient's teeth and adjacent gingival tissue. Thedigital data may be obtained by use of a hand-held intra-oral scanner orother device known in the art. As another option, the digital data maybe obtained by scanning an impression or a stone model. The replica 20may then be made from the digital data using, for example, a stereolithographic printer.

The replica 20 may also be made using digital data in conjunction with amilling process. For example, a CNC milling machine, similar to theCAD/CIM milling machines sold by Cerec Network of Buelach, Switzerland,may be used to mill replicas made of ceramic, composite or othermaterials. An intra-oral camera, similar to the cameras associated withthe Cerec machines, may be used to obtain digital data representing theshape of the dental arches. Alternatively, a scanner may be used to scanan impression or a model of an impression to obtain the digital data.

Preferably, the replica 20 is an accurate representation of thepatient's oral structure. In particular, the replica teeth 22 will havea configuration and orientation that is identical to the configurationand orientation of the corresponding teeth of the orthodontic patient.In addition, the replica gingival tissue 24 will have a shape thatmatches the shape of the corresponding portions of the gingival tissueof the patient.

Next, and as shown in FIGS. 2 and 3, a spacer material is applied to thereplica 20. In this example, the spacer material includes a first spacermaterial 26 that comprises a series of discrete dabs or pre-formedsegments of material that are placed at approximate, pre-determinedlocations on the replica teeth 22. Each of the dabs or segments ofspacer material 26 is placed in a location that corresponds to asubsequent location of an orthodontic appliance and has an overall sizethat is at least as large as the selected appliance. For instance, eachof the segments of spacer material 26 is placed in a locationcorresponding to the facial axis point (or “FA” point) of thecorresponding tooth, although other locations are also possible. As willbe described below, each of the segments of spacer material 26 functionsto subsequently provide clearance in the transfer apparatus forreceiving an orthodontic appliance.

As an alternative to segments of spacer material 26, the spacer material26 may instead have a elongated configuration in the form of a strip.The strip has sufficient length to extend across at least some, andpreferably all, of the replica teeth 22, following a path thatcorresponds to a subsequent position of an archwire. The strip hassufficient width to provide clearance for each of the appliances that issubsequently affixed to the archwire. In practice, spacer material inthe shape of a strip may be preferred in instances where the teeth arein general alignment (as the teeth appear in FIG. 1), while the spacermaterial in the shape of discrete segments or dabs may be preferred ininstances where the teeth are substantially crooked and/or out ofsubstantial alignment with each other.

In this embodiment, the spacer material also includes a sheet of spacermaterial 28 that preferably extends across a substantial portion of thesurfaces of the replica teeth 22 and preferably across at least aportion of the surface of the replica gingival tissue 24. As illustratedin FIG. 3, the sheet spacer material 28 also extends over the segmentsof spacer material 26. In the illustrated example, the sheet of spacermaterial 28 extends over the entire buccolabial surface area of thereplica teeth 22, along the occlusal edge of the replica teeth 22 andacross the entire lingual side of the replica teeth 22, although otherconstructions are also possible.

As another alternative, the spacer material 26, 28 may be provided as anintegral unitary section of material, such that separate handling of thetwo materials is avoided. Additionally, the sheet of material 28(whether alone, or whether integral with the spacer material 26) may bepreformed to a configuration that approximates the shape of a dentalarch. Such construction facilitates subsequent conforming of the sheet28 to the replica teeth 22 as will be described below.

The spacer material 26, 28 can be any one of a number of materials. Asuitable material is a silicone material, such as “RTV615” from GeneralElectric. Optionally, the spacer material 26 may be temporarily held inplace on the replica 20 by use of an adhesive, such as a pressuresensitive adhesive. Optionally, the segments or strips of spacermaterial 26 may be preformed, coated with a layer of pressure sensitiveadhesive on one side and initially connected to a sheet of releasematerial until such time as it is needed for use. Alternatively, dabs ofspacer material may be provided by dispensing a quantity of flowable,hardenable material from a syringe and then shaping each dab as neededwith a hand instrument.

Next, a vacuum is applied to the replica 20 and the spacer material 26,28 in order to form the sheet of spacer material 28 to the configurationof the replica teeth 22 and gingival tissue 24. As used herein, the term“vacuum” is not necessarily limited to an absolute vacuum, and shall beunderstood to mean any pressure that is lower than atmospheric. Inpractice, the replica 20 along with the spacer material 26 is placed ona disc-shaped support having channels communicating with the vacuumpump. The sheet of spacer material 28 is then placed over the replicaand the vacuum pump is activated to draw down the sheet of spacermaterial 28 into tight, matching conformance with the shape of thereplica teeth 22 and gingival tissue 24.

Subsequently, a tray 30 is formed over the spacer material 26, 28 asillustrated in FIG. 4. Preferably, the tray 30 is shaped by vacuumforming a sheet of material over the sheet of spacer material 28. Asuitable material for the tray 30 is a sheet of polycarbonate such asMakrolon brand material from Bayer or Lexan brand polycarbonate from GEhaving a thickness of 0.06 inch. Other materials, such aspolyethyleneterephthalate glycol (“PETG”) may also be used. Heat isapplied during the vacuum forming process in order to facilitateconformance of the sheet to the configuration of the sheet of spacermaterial 28.

Once the tray 30 has hardened, the tray 30 is detached from the spacermaterial 26, 28. The spacer material 26, 28 is then detached from thereplica 20 and set aside. Excess portions of the tray 30 may be trimmedas desired.

A thin layer of a release agent is then applied to the replica 20 andallowed to dry. An example of a suitable release agent is a watersoluble polyvinyl alcohol, such as “PA0810” from PTM & W Company ofSanta Fe Springs, Calif.

Next, a determination is made of the proper intended position of eachappliance on the replica teeth 22, corresponding to the ultimate desiredposition of the same appliance on the patient's corresponding tooth. Avariety of methods are available for determining appliance position. Forexample, the practitioner, practitioner's assistant or lab technicianmay make a pencil mark across the labial surface of each replica tooth22. The pencil mark is preferably made with the assistance of a heightgauge such as the MBT™ bracket positioning gauge or the Boone bracketpositioning gauge, both from 3M Unitek Corporation. The pencil line isdrawn across the labial surface of each replica tooth 22 to serve as alocation guide for placement of the archwire slot of each orthodonticappliance (such as an orthodontic bracket).

For example, and for the replica 20 representing the patient's lowerdental arch, pencil lines may be drawn parallel to the occlusal planeaccording to one treatment technique at a distance of 3.5 mm from theocclusal edge of the replica anterior teeth 22. Similar lines are drawnat a distance of 4.0 mm from the occlusal edge of the replica lowercuspid teeth 22 and the replica lower bicuspid teeth 22. Lines are alsodrawn parallel to the occlusal plane at a distance of 3.5 mm from theocclusal edge of each replica molar tooth 22 (unless the correspondingtooth of the patient will receive an appliance that is mounted on aband). In FIG. 5, some of the pencil lines as described above aredesignated by the numeral 32.

Next, orthodontic appliances 34 (such as orthodontic brackets and buccaltubes) as selected by the practitioner are placed on the correspondingreplica teeth 22, preferably in positions such that the archwire slot ofeach appliance 34 is approximately aligned with the respective pencilline 32. Before each appliance 34 is placed on the respective replicatooth 22, a quantity of a composition is placed between each applianceand the corresponding tooth 22. Preferably, the composition is alight-curable composition such as a light-curable adhesive, and theadhesive is coated across the base of each appliance 34.

Preferably, the appliances 34 are adhesive precoated appliances thathave a layer of light-curable adhesive applied by the manufacturer tothe base of each appliance 34. Such adhesive coated appliances aredescribed in U.S. Pat. Nos. 5,015,180, 5,172,809, 5,354,199 and5,429,229, all of which are assigned to the assignee of the presentinvention. The appliances 34 may be made of any suitable material suchas metal (e.g., stainless steel), ceramic (e.g., translucentpolycrystalline alumina) or plastic (e.g., translucent polycarbonate).

If the appliances 34 are not precoated with adhesive by themanufacturer, a coating of adhesive may be applied by the practitionerto the base of each appliance 34. Suitable adhesives include composites,compomers, glass ionomers and resin-modified glass ionomers. Examples oflight-curable adhesives include Transbond XT brand or Transbond LR brandadhesives from 3M Unitek. Examples of chemical curing adhesives includeConcise brand adhesive and Multi-Cure brand glass ionomer cement from 3MUnitek.

Once the appliances 34 have been placed on the replica teeth 22, theappliances 34 are shifted mesial-distally as needed to align the centralocclusal-gingival axis of the appliance 34 with the long axis of eachreplica tooth 22. The appliances 34 are also shifted in an occlusal orgingival direction as needed in order to place the archwire slot of eachbracket directly over the underlying pencil line 32. Optionally, a gaugesuch as the MBT™ gauge or Boone bracket positioning gauge mentionedabove is used again to precisely position the archwire slot of eachappliance 34 the distance specified above from the occlusal edge of thecorresponding replica tooth 22.

Next, the practitioner applies firm pressure to each appliance 34,preferably by using a scaler or other hand instrument to apply force tothe archwire slot of each appliance 34 in order to ensure that theappliance 34 is firmly seated on the replica tooth 22. A tool such as adental explorer is then used to remove any adhesive flash that may havebeen extruded near the periphery of the base of the appliance 34 duringseating.

The adhesive is designated by the numeral 36 in FIG. 6 and is notnecessarily drawn to scale. The use of a light curable adhesive 36 isadvantageous since an orthodontist's assistant or a lab technician cancarry out the steps described immediately above and then give thereplica 20 to the orthodontist or to a lab supervisor. The orthodontistor supervisor may then make a final check as to the precise placement ofeach appliance 34 on the corresponding replica tooth 22 before theadhesive 36 has hardened. As one example, a number of replicas 20 may beprepared by the assistant or technician and stored in an opaquecontainer such as a black plastic box until reviewed by the orthodontistor supervisor. In this manner, the orthodontist or supervisor can reviewthe placement of the appliances 34 on a number of different replicas 20at a convenient time without undue or premature curing of the adhesive36.

Once the accuracy of the appliance position has been confirmed, theadhesive 36 is allowed to harden. If a light-curable adhesive 36 isused, the replica 20 may be placed in a curing chamber such as Triad2000 brand visible light curing system from Dentsply. Preferably, thecuring chamber is sufficiently large to contain a number of replicas 20so that the adhesive 36 on a number of replicas 20 can be curedsimultaneously. In such a chamber, the light source and the replicas 20preferably move relative to each other during energization of the lightsource to facilitate curing of each portion of the adhesive 36.

If the appliances 34 are made of metal or other opaque material and if alight-curable adhesive 36 is used, it is preferable to expose thereplica 20 to the curing light for a relatively long amount of time suchas 3 to 5 minutes to ensure that the adhesive 36 has sufficientlyhardened. As an alternative to the light curing chambers mentionedabove, a hand-held curing unit may be used, such as Ortholux XT brandcuring unit from 3M Unitek.

As an additional option, the replica 20 including the replica teeth 22may be made from a material that transmits actinic radiation. Suitablematerials include epoxy resins that are transparent or translucent whenhardened. Preferably, the material is optically clear. An example of asuitable epoxy is E-CAST F-82 clear epoxy resin and No. 302 (or UCE-302)hardener, from United Resin Corporation. Other suitable materialsinclude polyesters and urethanes. The use of transparent or translucentmaterials is advantageous in instances where the appliances 34 are madeof opaque materials, since the actinic radiation can be transmittedthrough the replica 20 for curing portions of the adhesive 36 that arelocated adjacent the middle of the appliance base. Actinic radiation caninclude wavelengths in the visible range, ultraviolet range, infraredrange or any combination thereof, in accordance with the type ofphotoinitiator contained in the adhesive 36.

Alternatively, the appliances 34 may be placed on the replica teeth 22by means of robotic equipment. For example, the robotic equipment mayinclude a gripping arm that is programmed to pick an appropriateappliance 34 from a set of appliances and place the selected applianceon the appropriate replica tooth 22. The robotic arm then proceeds tograsp another appliance 34 for placement on another replica tooth 22.

Optionally, the path of movement of the robotic arm and the ultimateposition of the placed appliance 34 are determined by computer softwarethat has access to digital data representing a virtual model of thereplica 20. The software preferably includes subprograms suitable toanalyze the existing malocclusion of the patient and select properappliances for treatment of the particular malocclusion at hand.Optionally, the software enables the practitioner, patient or otherobserver to see on a monitor or other video output a virtualrepresentation of the patient's teeth as they should appear at theconclusion of treatment using the selected appliances placed on certainlocations of the teeth.

Preferably, the software includes subprograms for selecting appliances,analyzing malocclusions and/or predicting tooth movement and finalpositions of the teeth. An example of software for choosing appliancesis described in pending U.S. patent application Ser. No. 10/081,220entitled “Selection of Orthodontic Brackets”, the disclosure of which isexpressly incorporated by reference herein. Optionally, the softwareincludes subprograms for making custom orthodontic appliances using, forexample, a computer numerical control milling machine, instead ofselecting appliances from an existing set of appliances as mentionedabove. As an additional option, an orthodontic archwire may be placed inthe slots of the appliances 34 and ligated in place. This step serves tofurther reduce the patient's time that is subsequently spent in thechair.

The replica 20, together with the appliances 34 (and the archwire, ifany), represent a treatment model 38 of an orthodontic patient set-up asshown in FIG. 5. A matrix material is then applied, either to the model38 or to the-channel of the tray 30. For example, if the matrix materialis relatively viscous and resembles a semi-liquid or gel, the matrixmaterial may be applied to the model 38 as it appears in FIG. 5, using asyringe, brush or other technique. Alternatively, if the matrix materialhas a relatively low viscosity and resembles a liquid, it may bepreferable to invert the tray 30 such that the open side of the channelof the tray 30 is facing upwardly as shown in FIG. 6. If the tray 30 isinverted, the tray 30 is not initially trimmed along the outermostdistal sides (corresponding to the ends of the dental arch) so that theliquid matrix material is contained within the tray channel.

Subsequently, the model 38 is positioned in the tray 30 such that thematrix material is received, in the channel of the tray 30 and betweenthe tray 30 and the model 38. In FIG. 6, the matrix material isdesignated by the numeral 40 and surrounds the appliance 34 as well asthe labial and lingual surfaces of the replica tooth 22. The matrixmaterial 40 is then allowed to harden.

Preferably, the matrix material has a relatively low viscosity beforehardening so that intimate contact between the matrix material 40 andthe appliance 34 is assured. In this manner, the matrix material 40 isable to substantially penetrate in various recesses, cavities and otherstructural features of the appliance 34 so that a secure connectionbetween the appliance 34 and the matrix material 40 can be established.An example of a suitable matrix material having a relatively lowviscosity is a silicone material such as “RTV615” silicone material fromGeneral Electric as mentioned above. The relatively low viscosity ofthis silicone matrix material also assures that the matrix material willassume a configuration that closely matches the shape of the adjacentsurfaces of the replica teeth 22.

Alternatively, the matrix material 40 may comprise a dental impressionmaterial or a bite registration material. Suitable materials includepolyvinylsiloxane impression material, such as Memosil 2 brand vinylpolysiloxane material from Heraeus Kulzer Inc., or Peppermint Snap brandclear bite registration material from Discus Dental. If a light-curableadhesive is to be used for bonding the appliances 34 to the patient'steeth, the matrix material 40 is preferably optically clear andtransmits actinic radiation without substantial absorption.

Once the matrix material 40 has hardened, the tray 30, together with thematrix material 40 and the appliances 34, are detached from the replica20. The use of the release agent as mentioned above helps facilitatedetaching of the appliances 34 from the corresponding replica teeth 22.Excess material of the tray 30 and excess matrix material 40 is thentrimmed as desired and discarded. The resultant trimmed transferapparatus 44 (comprising the tray 30, the matrix material 40 and theappliances 34) is shown in cross-sectional view in FIG. 7.

Once the patient has returned to the office, the patient's teeth thatare to receive appliances are isolated using cheek retractors, tongueguards, cotton rolls, dry angles and/or other articles as needed. Theteeth are then thoroughly dried using pressurized air from an airsyringe. Etching solution (such as 3M Unitek Transbond XT brand etchinggel) is then dabbed onto the teeth in the general area that is to becovered by the appliances 34, taking care to prevent the etchingsolution from flowing into interproximal contacts or engaging the skinor gingiva.

After the etching solution has remained on the selected tooth surfacesfor a period of approximately 30 seconds, the solution is rinsed awayfrom the teeth with a stream of water for 15 seconds. The patient'steeth are then dried by the application of-pressurized air from an airsyringe (for example, for a time period of 30 seconds) and excess wateris removed by suction. Care should also be undertaken to ensure that thesaliva does not come in contact with the etched enamel surfaces. Cottonrolls and other absorbent devices are replaced as needed, again makingsure that saliva does not contact the etched enamel. Air from the airsyringe may then be applied to the teeth again to ensure that the teethare thoroughly dried.

Next, a bonding adhesive is applied to the hardened adhesive 36 and/orthe selected areas of the patient's teeth. Optionally, the adhesive is atwo-component adhesive as depicted in FIG. 7. For example, the firstcomponent 41 is a Transbond brand MIP moisture insensitive primer, andthe second component 43 is Transbond brand Plus self-etching primer,both from 3M Unitek. The first component 41 is applied to the hardenedadhesive 36 and the second component 43 is applied to the area of thepatient's tooth that is to receive the appliance 34. In FIG. 7, thepatient's tooth is designated by the numeral 42.

After the first component 41 has been applied to the hardened adhesive36 and the second component 43 has been applied to the correspondingarea of the patient's tooth 42, the tray 30 is then positioned over thecorresponding teeth and seated, optionally with a swinging, hinge-typemotion. Since the shape of the cavity of the matrix material 40 matchesthe shape of the underlying teeth, the appliances 34 are simultaneouslyseated against the underlying teeth 42 at precisely the same locationscorresponding to the previous position of the appliances 34 on thereplica 20. Preferably, pressure is then applied to the occlusal, labialand buccal surfaces of the tray 30 until such time as the bondingadhesive has sufficiently hardened. Optionally, finger pressure may beused to firmly press the appliances 34 against the enamel surfaces ofthe patient's teeth 42.

Other examples of suitable two-component chemical curing adhesivesinclude Sondhi brand Rapid-Set indirect bonding adhesive, Unite brandadhesive and Concise brand adhesive, all from 3M Unitek. Alternatively,a resin-modified glass ionomer cement may be employed.

Once the bonding adhesive has hardened, the tray 30 is carefully removedfrom the patient's dental arch. Preferably, the tray 30 is firstseparated from the matrix material 40, which remains in place over thedental arch along with the appliances 34. Next, the matrix material 40is detached from the appliances 34. Optionally, a hand instrument suchas a scaler may be used to help hold each appliance 34 against thesurface of the respective tooth 42 of the patient as the matrix material40 is peeled away from the appliances 34. However, in instances where arelatively soft matrix material is employed or otherwise readilyreleases from the appliances 34, the use of a scaler to help avoidfracturing the fresh adhesive bond is optional.

As another option, the tray 30 may be separated from the matrix material40 before the bonding adhesive has hardened. This option is particularlyuseful when the bonding adhesive is a light-curable adhesive.

Once the matrix material 40 has been detached from the appliances 34, anarchwire is placed in the slots of the appliances 34 and ligated inplace. Suitable ligation devices include tiny, elastic O-rings as wellas sections of wire that are tied in a loop around the appliances 34. Asanother option, the appliances 34 may be self-ligating appliances thatinclude a latch for releasably engaging the archwire such as thosedescribed in U.S. Pat. No. 6,302,688 and PCT Publication No.W002/089693.

As can be appreciated, the hardened adhesive 36 provides a contouredbonding surface for the base of the corresponding appliance 34. Theconfiguration of this bonding surface closely matches the shape of thepatient's tooth surface and consequently facilitates the subsequent bond(using the bonding adhesive components 41, 43) that is establishedbetween the appliance 34 and the tooth 42. The bonding surface reducesthe likelihood that the appliance 34 will become unintentionallydetached from the tooth during the course of treatment.

The use of the spacer material 26, 28 in the method described above is asignificant advantage in that an appropriate region for receiving matrixmaterial 40 in the tray 30 is provided. The spacer material 26, 28 canbe shaped as needed to provide precisely the volume and configuration ofregion as may be desired. For example, the sheet of spacer material 28ensures that a uniform thickness of matrix-material is subsequentlyprovided around the substantial extent of the tooth 42 with theexception of the areas adjacent the appliance 34.

Moreover, the use of the spacer material 26, 28 facilitates the use of amatrix material having a relatively low viscosity, such as a matrixmaterial having a liquid consistency. The tray 30 is relatively stiff,and consequently maintains its shape during forming of the matrixmaterial 40. As a result, the transfer apparatus 44 is constructed suchthat the tray 30 does not directly contact the patient's teeth orgingival tissue. Instead, only the matrix material 40 comes into contactwith the patient's teeth, so that a close, matching fit with such oralstructure is provided.

Another advantage of the present invention is that the relatively softmatrix material 40 is flexible and can accommodate a limited amount oftooth movement. For example, the teeth of the patient may have slightlyshifted between the time that the impressions are taken and the timethat the transfer apparatus 44 is fitted in the patient's oral cavityfor bonding the appliances 34. The matrix material 40 has sufficientflexibility to comply with small shifts or adjustments in the patient'stooth positions, so that the appliances 34 are properly bonded to theintended, pre-determined locations on the patient's tooth.

The matrix material 40 preferably has a viscosity before curing that isless than about 60,000 cp. More preferably, the matrix material 40 has aviscosity before curing that is less than about 25,000 cp. Mostpreferably, the matrix material 40 has a viscosity before curing that isless than about 8000 cp. Once hardened, the matrix material 40 has aShore A hardness that is in the range of about 10 to about 80, morepreferably in the range of about 30 to about 60 and most preferably inthe range of about 40 to about 50.

Furthermore, the use of the spacer material 26, 28 enhances control overconstruction of the transfer apparatus, including the resultant shape ofthe tray 30 and the contained matrix material 40. For instance, thesheet of spacer material 28 enables the resultant thickness of thematrix material 40 to be relatively uniform and preferably relativelythin. This uniform thickness of relatively small dimension facilitatescuring of a photocurable adhesive used to bond the appliances to thepatient's teeth. Specifically, when a light-curable adhesive is used tobond the appliances 34 to the patient's teeth, the uniform thickness ofmatrix material 40 helps to ensure that the light-curable adhesivebeneath each appliance 34 is sufficiently cured to the same extent fromone appliance 34 to the next. In this manner, the user need notcompensate for varying thicknesses of matrix material and the curingtimes associated with each quantity of adhesive need not vary from oneappliance 34 to the next.

A transfer apparatus 44 a constructed in accordance with anotherembodiment of the invention is shown in FIG. 8. The transfer apparatus44 a includes a tray 30 a having a channel and a matrix material 40 athat is received in the channel. Except as described, the tray 30 a andthe matrix material 40 a are substantially identical to the tray 30 andthe matrix material 40 set out above.

The transfer apparatus 44 a includes a passageway that extends next to acavity 45 a of the matrix material 40 a. The cavity 45 a has aconfiguration matching the replica of the patient's teeth. Thepassageway in the embodiment shown in FIG. 8 is provided within a lengthof flexible tubing 46 a, although other types of passageways are alsopossible.

The tubing 46 a has a series of small holes that are open to the cavity45 a. The tubing 46 a also includes an outlet section 48 a that extendsthrough the matrix material 40 a and the tray 30 a in approximately themesial-distal center of the transfer apparatus 44 a. The ends of thetubing 46 a that are located adjacent the distal ends of the cavity 41 aare closed.

Preferably, a channel or passage 66 a extends from the tubing 46 a tothe hardened adhesive 36 a of each appliance 34 a. The passage 66 a maybe made by placing a length of wire, string or monofilament cord alongthe replica tooth before placing the matrix material between the tray 30and the replica tooth. Once the matrix material has hardened, the stringor cord is removed, leaving the passage 66 a.

The outlet 48 a is connected to a source of vacuum. Once the transferapparatus 44 a is placed over the patient's tooth structure during abonding procedure, the source of vacuum is activated. As vacuum pressureis applied, air is evacuated from the cavity 45 a. The resultingnegative pressure in the cavity 45 a tends to draw the matrix material40 a and the tray 30 a toward the patient's tooth structure, such thatthe appliances (including the appliance 34 a) held by the matrixmaterial 40 a are firmly pressed against the enamel surfaces of thepatient's teeth.

The vacuum is applied to the outlet 48 a until such time as the bondingadhesive for bonding the appliances to the patient's teeth has hardened.Subsequently, vacuum pressure is relieved and pressure in the cavity 45a returns to atmospheric pressure. The tray 30 a and the matrix material40 a are then removed, leaving the appliances 34 a firmly bonded to thepatient's teeth.

A transfer apparatus 44 b according to another embodiment of theinvention is illustrated in FIG. 9. Except as described below, thetransfer apparatus 44 b includes a tray 30 b and a matrix material 40 bthat are essentially identical to the tray 30 a and matrix material 40 adescribed above and illustrated in FIG. 8.

The transfer apparatus 44 b includes one or more bladders 50 b that canbe pressurized by a fluid such as pressurized air. A cross-sectionalview of one bladder 50 b is illustrated in FIG. 9. The bladder orbladders are connected by a conduit or passageway to an inlet 52 bwhich, in turn, is detachably connected to a source of fluid such aspressurized air.

The bladder(s) 50 b are located between the tray 30 b and the matrixmaterial 40 b in a location opposite the appliances (such as appliance34 b). During a bonding procedure, pressurized air is admitted throughthe inlet 52 b and directed to the bladder(s) 50 b. As the bladder(s) 50b expand, the transfer apparatus 44 b is urged in a direction toward thebladder(s) 50 b and causes adhesive 36 b on the base of the appliances34 b to bear against the adjacent surface of the patient's tooth.

In the illustrated example, a bladder 50 b is located along the lingualside (i.e., a tongue-facing side) of the patient's dental arch when thetransfer apparatus is placed in the patient's oral cavity. Theappliances 34 b are buccolabial appliances adapted for bonding to thebuccolabial surfaces of the patient's tooth (i.e. surfaces of the tooththat face the patient's lips or cheeks). As the bladder 50 b expands,the transfer apparatus 44 b along with the appliances 34 b are urged ina lingual direction.

However, the concepts exemplified in FIG. 9 may also be adapted for usein bonding of lingual appliances to lingual surfaces of the patient'steeth. For example, the bladder(s) 50 b may extend along the buccolabialside of the patient's dental arch in a position between the matrixmaterial 40 b and the tray 30 b. The appliances 34 b are positioned inthe matrix material 40 b along the lingual side of the patient's dentalarch. As the bladder(s) 50 b expand in this example, the transferapparatus 44 b is urged in a buccolabial direction and causes the baseof the appliances 34 b to firmly bear against the lingual surfaces ofthe patient's teeth.

In the embodiments of FIGS. 8 and 9, the positive or negative airpressure, in conjunction with the bladder(s) or passageways, tends tofirmly hold the base of the appliances in contact with adjacent enamelsurfaces of the patient's tooth. Such firm contact facilitatesestablishing a relatively high bond strength between the appliances andthe teeth. In addition, such construction helps resist unintentionalmovement of the transfer apparatus 44 a,44 b as the adhesive is curing,as might otherwise occur if the patient's jaws move or if the transferapparatus is bumped before the time that the bonding adhesive hassufficiently hardened.

A transfer apparatus 44 c according to another embodiment of theinvention is illustrated in FIG. 10. The transfer apparatus 44 cincludes a tray 30 c and a matrix material 40 c. Except as describedbelow, the tray 30 c and the matrix material 40 c are essentially thesame as the tray 30 and matrix material 40 as set out above.

The transfer apparatus 44 c includes a cord 66 c that is at leastpartially embedded in the matrix material 40 c. Preferably, the cord 66c is elongated and flexible, and optionally is a string made of nylon orother material. The cord 66 c generally extends in a direction along thelongitudinal axis of the cavity of the matrix material 40 c.

The cord 66 c facilitates removal of the matrix material from thepatient's oral cavity after the bonding procedure is complete. Forexample, after the tray 30 c has been detached from the matrix material40 c, the practitioner may pull on a free end of the cord 66 c thatextends out of the matrix material 40 c. As the cord is pulled, thematrix material fractures along the path of the cord, such that thematrix material 40 c is split (or essentially split) into two sections.The two sections can then be easily removed from the oral cavity asdesired, reducing the likelihood that the bond between the appliance 34c and the patient's tooth will be disturbed.

In the embodiment shown in FIG. 10, the cord 66 c extends in the cavityof the matrix material 40 c along a path that approximately correspondsto the occlusal edge of the patient's dental arch. The transferapparatus 44 d shown in FIG. 11 is somewhat similar. However, in thetransfer apparatus 44 d, a cord 66 d extends along a location generallycorresponding to the intended path of the archwire. Such constructionfacilitates release of the matrix material 40 d from the appliances andmay be especially desirable in instance where the appliances aresecurely connected to the matrix material 40 d.

A variety of other embodiments are also possible and will be apparent tothose skilled in the art. For example, in the embodiments shown in FIGS.8–11, the tray may be omitted provided the matrix material hassufficient strength and rigidity. Moreover, the various featuresdescribed in the figures may be combined with one another.

As another option, the transfer apparatus described in the variousembodiments above may be used for bonding appliances such as brackets,buccal tubes and lingual sheaths to the lingual surfaces of thepatient's teeth. In that instance, the bladders and cords, if utilized,are adapted and modified as needed.

Additionally, the transfer apparatus may be used for bonding only asingle appliance to a patient's tooth. For example, a portion of thetransfer apparatus described above may be used to bond a singleappliance to a single tooth subsequent to the time that other appliancesare bonded, such as in instances where access to the tooth is initiallyhindered by other teeth. As another example, a portion of the transferapparatus described above may be used to re-bond an appliance that hasunintentionally debonded from the tooth, or to bond a new appliance to atooth to replace the original appliance.

A number of other variations, modifications and additions are alsopossible without departing from the spirit of the invention.Accordingly, the invention should not be deemed limited to the specificembodiments described above, but instead only by a fair scope of theclaims that follow and their equivalents.

1. A method of making orthodontic transfer apparatus for indirectbonding of one or more orthodontic appliances comprising: making areplica of a patient's tooth structure; placing a spacer material overat least a portion of the replica; forming a tray over at least part ofthe replica including at least part of the spacer material; removing thetray from the replica and from the spacer material; detaching the spacermaterial from the replica; placing one or more orthodontic appliances onthe replica to make an orthodontic treatment model; applying a quantityof matrix material to either the tray or to the model; positioning thetray over the model such that the matrix material is received betweenthe tray and the model; and allowing the matrix material to harden.
 2. Amethod of making orthodontic transfer apparatus according to claim 1wherein the matrix material has a Shore A hardness that is in the rangeof about 10 to about
 80. 3. A method of making orthodontic transferapparatus according to claim 1 wherein the matrix material has a Shore Ahardness that is in the range of about 30 to about
 60. 4. A method ofmaking orthodontic transfer apparatus according to claim 1 wherein thematrix material is a curable material and has a viscosity before curingof less than about 60,000 cp.
 5. A method of making orthodontic transferapparatus according to claim 1 wherein the matrix material is a curablematerial and has a viscosity before curing of less than about 25,000 cp.6. A method of making orthodontic transfer apparatus according to claim1 and including the act of providing a passageway adjacent the matrixmaterial in order to apply vacuum pressure when the appliance(s) areplaced on the patient's tooth structure.
 7. A method of makingorthodontic transfer apparatus according to claim 6 wherein the act ofproviding a passageway includes the act of placing a section of tubingalong a path that is next to the occlusal edge of the replica.
 8. Amethod of making orthodontic transfer apparatus according to claim 6wherein the act of providing a passageway includes the act of placing asection of tubing along a path that is next to the appliance(s).
 9. Amethod of making orthodontic transfer apparatus according to claim 1 andincluding the act of positioning a flexible bladder in the matrixmaterial in order to provide an application of pressure when theappliance(s) are placed on the patient's tooth structure.
 10. A methodof making orthodontic transfer apparatus according to claim 1 andincluding the act of placing a hardenable material between at least oneappliance and the replica to make a contoured bonding surface.
 11. Amethod of making orthodontic transfer apparatus according to claim 10wherein the hardenable material is a photocurable material and alsoincluding the act of directing actinic radiation through at least aportion of the replica in order to harden the photocurable material. 12.A method of making orthodontic transfer apparatus according to claim 1and including the act of placing an elongated cord in the matrixmaterial to facilitate detaching the matrix material from theappliance(s).
 13. A method of making orthodontic transfer apparatusaccording to claim 1 wherein the act of making a replica is carried outusing digital data.
 14. A method of making orthodontic transferapparatus according to claim 1 wherein the act of making a replica iscarried out using a curable material.
 15. A method of making orthodontictransfer apparatus according to claim 1 wherein the act of placing oneor more orthodontic appliances on the replica is carried out usingrobotic equipment.
 16. A method of making orthodontic transfer apparatusaccording to claim 1 wherein the act of placing one or more orthodonticappliances on the replica is carried out by hand.
 17. A method of makingorthodontic transfer apparatus according to claim 1 wherein the act ofpositioning the tray over the model is carried out by orienting the traysuch that a channel of the tray is open in an upward direction.